Generally, in a load lifting unit of a lift truck, especially, of a counterbalance type lift truck, a lift cylinder for lifting and lowering a lift member including a fork carriage etc. and a support means such as lift roller etc. are arranged at a central portion between left and right uprights. Thus, the lift cylinder is positioned in front of the driver's seat, so that a wide region of the driver's forward view is obstructed.
Therefore, it is difficult to clearly see signs or obstructions or to watch the front end portion of a fork. This load lifting unit has various problems in safety and operating efficiency. In addition, since the lift cylinder is disposed at such a central portion between the uprights, an attachment such as a side shift fork, a hinged fork, a fork with a winch, a rotating clamp, or a reach fork must be mounted in such a way that the base portion of the attachment is fixed to the lift member so as not to interfere with the lift cylinder. To meet this requirement, the attachment is generally mounted on the fork carriage which is located at the forward position of the uprights. Therefore, the distance between the load center position of the attachment and the center of the front wheels is long. Moreover, since the attachment had its own actuating mechanism, the load center position is moved further forward away from the truck body. As a result, the permissible load of the lift truck is so reduced that a load lifting operation attainable by using a conventional fork cannot be effected, and it is possible to obtain only the loading capacity of a less powerful lift truck when the above-mentioned attachment is attached to the truck in place of the conventional fork. To overcome a significant reduction in the loading capacity, it has been proposed to reduce the thickness of the attachment, especially, of the actuating mechanism thereof, to recover the lost loading capacity. In the case of, for example, the rotating clamp or the rotating fork, it has been proposed to reduce the thickness of the rotator gear of a rotator while increasing the diameter thereof. However, if the thickness of the components of the attachment is reduced, the size of the component in a vertical plane should be increased to obtain the desired mechanical strength of the components. Therefore, the height of the attachment and the projected area of the attachment in the vertical plane are increased, and accordingly, the frontward view is further obstructed and the visible range for the forward operation from the driver's seat is greatly narrowed. In this connection, a countermeasure for improving the forward view from the driver's seat of the lift truck has been proposed. A specific example of the proposal was disclosed in Japanese Patent Publication No. Sho 49-29661. However, there has not yet been proposed a countermeasure which can attain both an improvement in the forward view and an increase in the permissible load while further attaining positive promotion of safety.